Question

Consider the following statements:

If the maximum range of radar has to be doubled

1. the peak transmitted power may be increased 16 folds

2. the antenna diameter may be doubled

3. the sensitivity of receiver may be doubled

Which of the above statements are correct? 

1. 1 only
2. 2 and 3
3. 3 and 4
4. 1 and 4

Answer 1

Correct Answer - Option 1 : 1 only

Concept:

The range of the radar is given as:

\(R = {\left[ {\frac{{{P_t}{G^2}\sigma {A_e}}}{{{{\left( {4\pi } \right)}^2}{P_r}}}} \right]^{\frac{1}{4}}}\)

G= Antenna Gain

σ = Radar Cross-Section

Pr = Reflected Power

Ae = Effective Area of the Antenna

Observations:

• Since R_max ∝ (Pt)^1/4, to double Rmax, Pt must be increased by a factor of 16.
• Since R_max ∝ D^1/2, If the antenna aperture is doubled i.e. if the diameter is doubled, the radar range will be increased by √2.